Concurrent tunable structural color, luminescence, and afterglow in single ZnS: X@SiO2 spheres via SiO₂-nanoarmor and...

The integration of structural color, photoluminescence, and afterglow into a single material remains a fundamental challenge due to the conflicting requirements for structural integrity and high-temperature crystallization. Here, we present a SiO ₂ -nanoarmor and calcination decoupling collaborative strategy to create monodisperse wurtzite-type ZnS: X@SiO₂ spheres (X = Ag⁺, Cu²⁺, Mn²⁺) as a unified, single-particle optical platform. Spatially, a conformal SiO₂ nanocoating acts as a thermally stable scaffold, preserving perfect spherical morphology during solid-phase transformation at 1000°C, thereby enabling angle-independent structural colors across the visible spectrum via Mie resonance. Calcination decoupling was achieved through an alternating O₂/N₂ atmosphere, which removes carbon deposits at low temperature and subsequently drives a complete sphalerite-to-wurtzite phase transition with 91% conversion, while preventing oxidation. Programmable doping introduces engineered energy levels, enabling tunable photoluminescence from 490 nm (blue) to 600 nm (orange) and white emission through co-doping. The fluorescence quantum yield was 12.8%. Notably, Cu- and Mn-doped spheres exhibit green afterglow lasting up to 12.27 s, and their duration was controlled by the content of the wurtzite phase. This intrinsic multifunctionality allows sophisticated multi-channel optical encryption, where a single pattern sequentially displays distinct information under natural light, UV illumination, and afterglow conditions.